PHP

Last Updated on June 11, 2025 by বিডি কিক

What is PHP

• Full form of PHP – Hypertext Preprocessor
• Server scripting language, powerful tool/language for making dynamic websites

Note: The main difference between Scripting and Programming Language is – “Scripting language need interpreter, but programming language need compiler.

Why PHP

• Popular, full free, and efficient
• Flexible
• Open source general-purpose scripting language
• Specially suited for web development and can be embedded into HTML.
• Best Part: PHP is that it is extremely simple for a newcomer,

What can do PHP

• Server-side scripting: CGI features
• Command line scripting
• Writing desktop applications

History of PHP

• First PHP created by Rasmus Ledorf at 1994 (Made by (CGI) binaries written in the C programming language)
  
• Reason: Tracking visits to his online resume, so he named it Personal Home Page Tools, short form PHP tools

Environment Setup & Editor Setup for PHP

• Xampp
• Code Editor – Visual Studio Code
• Web Browser – Google Chrome

PHP Syntax

Create a php file, a php file extension must be php.

// Opening and Closing PHP tag

<?php
   //php code
?>

// Short echo tag

<?=  ?>

Note 1: Short echo tag can be enable/disable by php.ini file
// Opening and Closing PHP tag

<?php
   //php code
?>

// Short echo tag

<?=  ?>

Note 1: Short echo tag can be enable/disable by php.ini file
// Opening and Closing PHP tag

<?php
   //php code
?>

// Short echo tag

<?=  ?>

Note 1: Short echo tag can be enable/disable by php.ini file
Note 2: If your PHP files contain only PHP code, it's preferable to skip the PHP closing tag

Statement, echo, print, PHP and HTML

Statement: A line of code.
echo: output string and variable (can be used with or without parentheses)
print: output string and variable (can be used with or without parentheses)

Note: echo is faster compare to print.

PHP and HTML

• PHP and HTML code can use in same file, ensure your file is a php file.
• Live

Variable and Constant

• Variable: Variable is a value, data which can change.
• Constant: Constant is also one type variable, but this value can’t be change while program is running.

Variable Name can be define by different way:
Camel Case: $myName
Pascal Case: $MyName
Snake Case: $my_name

Variable and Constant – Naming Convention

• Must be start with $ sign
• Must be start with Alphabet or Underscore
• Name can contain alpha-numeric characters and underscores (A-z, 0-9, and _ )

Note: Variable name are Case Sensitive.

Magic Constant

Magic constant are some pre defined constant by PHP, it’s change dynamically his value based on where it’s using.

    // print the line no
    
    
    echo '__LINE__ This instruction line number ' . __LINE__ . "<br>";  



    // print the file directory including file name
    echo '__FILE__ This file directory  ' . __FILE__ . "<br>";  
   

     // print the directory
    echo '__DIR__ This file directory ' . __DIR__ . "<br>";  


    // print the function name

    function my_sujon(){
        echo '__FUNCTION__ This statement from function ' . __FUNCTION__ . "<br>";  
        
    }


    
    my_sujon();

Operators

Operator Type	Operators
Arithmetic Operators	Addition (+) Subtraction (-) Multiplication () Division (/) Modulus (%) Exponentiation (**)
Assignment operators
Comparison operators	Equal (==) Identical (===) Not equal (!=) Not equal (<>) Not identical (!==) Greater than (>) Less than (<) Greater than or equal to (>=) Less than or equal to (<=) Spaceship (<=>)
Increment/Decrement operators	Pre-increment (++$i) Post-increment ($i++) Pre-decrement (–$x) Post-decrement ($x–)
Logical operators	And (and) Or (or) Xor (xor) And (&&) Or (||) Not (!)
String operators	Concatenation (.) Concatenation assignment (.=)
Array operators	Union (.) Equality (==) Identity (===) Inequality (!=) Inequality (<>) Non-identity (!==)
Conditional assignment operators	Ternary (?:) Null coalescing (??)

PHP Data Types

There are mainly 8 datatypes in PHP.

1. String
2. Integer
3. Float (floating point numbers – also called double)
4. Boolean
5. Array
6. Object
7. NULL
8. Resource

Data Types	Description
String	When a variable store character or text, it’s a String. Example: $x = “abc”; Note: String can wrap with single quote or double quote.
Integer	Integer means the number, which can have a negative or positive value, but not a decimal point. Integer has a limit, it depends on the computer bit.
Float	Float means the decimal point number.
Boolean	Boolean use for conditional testing. True and False can be values of a boolean type variable. (Case Insensitive)
Array	Array is one kind of date type, which can store multiple data at a time.
Object	Object use for OOP
NULL	Null mean where you have assign nothing, also you can assign null. (Special Type)
Resource